Glutathione-sensitized SnS2 nanoflake/CdS nanorod heterojunction for enhancing cathodic protection of 304 stainless steel with remarkable photoelectric conversion performance.

[Display omitted] • SnS 2 flakes/CdS rods nanocomposite was synthesized by a two-step hydrothermal method. • Glutathione was introduced as both a structural guide and a hole absorber. • SnS 2 /CdS/GSH had optimal photocathode protection effect compared with SnS 2 /CdS. • The OCP of 304 SS coupled with SnS 2 /CdS/GSH decreased by 320 m V after light. An effective way to enhance photochemical performance can be achieved by optimizing the microstructure of composite semiconductor materials. Here, a two-step hydrothermal method was used to synthesize SnS 2 /CdS composite photoanodes for photocathode protection applications, and glutathione was introduced as a structure-directing agent to enhance the separation efficiency of photogenerated electron-hole pair of SnS 2 /CdS. In the presence of glutathione, SnS 2 became a smaller and thinner nanoflake and hexagonal CdS extended into a rod shape, the combination of them resulted in larger light collection area and higher charge transfer rate. The electrochemical test results demonstrated that the open circuit potential of 304 SS coupled with SnS 2 /CdS/GSH photoanode was negatively shifted to about −0.5 V under light, which not only far exceeded the self-corrosion potential of 304 SS (-0.18 V), but also improved from −0.42 V of SnS 2 /CdS. Further, the photogenerated current density of SnS 2 /CdS/GSH was nearly three times that of SnS 2 /CdS, EIS and polarization curve results also indicated that glutathione enhances the PEC performance of SnS 2 /CdS. Obviously, the type-II heterojunction formed by glutathione-sensitized SnS 2 /CdS provides more electrons for 304 SS, which is beneficial to achieve better photocathodic protection. [ABSTRACT FROM AUTHOR]